Variable condenser



May 7, 1929 H. R. VAN DEvl-:NTR

VARIABLE CONDENSER Filed April 25, 1925 .Patented May i", 19,25%a

UNITED STATES EARRY R. VAN DEVENTER, Gli' NEVI YORK, N'. Y., SSG-TEDUBLIER illfi c CORRATION, YORK, N. Y., A CORGRATON F DELAWARE..

VARIABLE CONDENSER.

Application filed .April 23,

clensers.

An object of my invention is to provide a 5 condenser in which theadjustment of the relative positions of the condenser elements isaccomplished with the minimum of friction oi the parts.

Another object of my invention is to inake a condenser structure inwhich the condenser elements are resiliently held in close contact -forthat portion of their surfaces that are in operative relationship toeach other, at any given setting ot tnecontienser,

A further object of my invention is to provitle :i condenser soconstructed that the means for effecting-' the acl'iistinents can helocated on either sicle of the housing. thus making the contlenseradapted to a, Wide variety ot uses..

.fi still {nrt-her object ot my invention is to show how to construct avariable condenser that is sturdy, and capable of use by unskilledpersons for long periods ot time Without the necessity of repair orreplacement.,

Figure l is a view in longitudinal section oi niy flevice taken on aplane passing through the axis of the rotor shaft;

l 2 is a bottoni plan View o'liny Tvariable condenser with part of thecover plate broken away to more clearly show the posit-ion et the parte;l

Fig. 3 is a view in cross section oi my device taken on the line 3 3 ofFig. fi, looking in the direction oi the arrows;

Fig. 4; is a detail View in perspective of the retaining spring;

Fig. 5 is a detail view in perspective of the rotor;

Fig. 6 is a View in sicle elevation of iny variable condenser with aportion oi the casingV hrolen away., showing the adaptation of thecondenser wherein an extension sha ft is inounteii on the cover platesitle;

Figi. 7 a detail View in perspective of the :nljustahle element. of mycondenser.

I have illustrated my invention as coinprisingf a casing l of sonicsuitable insulating material sncli as hard rubber or Aiakeiite.

Wall of the housing for the va iiahle condenser. The casing; l has anupwardly extending cylindrical portion 3 Within which is journalecl'conducting foil i4 and is preferably 1923. Serial No. 634,097.

a metallic shaft 4. The metailic s formed with apertures at either endAs shown in the drawings, eperti entends the entire distance thronkvlith ter of the shaft and is screw-tliieitleil. lonfer end of the aperture5 is slightlv ened, as inicated et t?, thereby ini conical seat 7. i

Formeel on the'shait 4, nrei. tegrelly made therewith, is e shov xvhichhave shown as et Square conti tion, over which is adapted to tit an ti 9centrally formed in e rotor l1 et insuiw material. The rotor ll isprovifieci fvi'tii e slot l2 therein which is set en an i e raclii ofthe rotor. The slot, l2 isini with beveledr edges i3. The iit ioetifaperture 9 and; 'the shoulder 8 oi" the sh is not a 'tight it, l3nt therotor is ada tient on the shoulder 8 and he cii ready movement in thedirection of in of the shaft 4r.

Mounted against the upper' inte oi the casing l is an annular tixeal conplate lll preferably formed o metall-.c i. The condenser plete le titsinto e recess orrnecl in the casing, and a metallic eye i6 is atieptedto pass through the sheet or plate of; nietaliic toil li and to maire fthrough @holding contat. p cw L.. i c cyelet lo is iiveteoi in @lace toene connection permanent. 'doveiing` conducting sheet Llis aninsulatingr sheet o inica 18 which is in close reletionsiiin te 'ined ofthereto by a suitable adhesive.

The flexible condenser element comprises a iriexilile strip ot nieta-l.19 of annular con-1 formation, see Fig. 7. This metallic strip has a.convolute intension ivliicli tends to spring,y e it out, as shown inFig. 'i'. l@ne edge of the free enti et the lexilile eleii'ient iii isin tiu'iie, as intlicated at QG. The liexilile eleinent 19 is providedwith a relativeiy witie neel: 2l exteneine' into an aperture 22 iorinetiin the casing l. An eyelct 23 ina-lies 'contact with the flexibleelement i9 through s. holding contact member Q4. The eyelet- 23 is riveted in place ancl makes permanent electrical connection. with theiexible sheet The free enel of the i'iexiale element is adapted to slidethrough the slot 12 in the rotor 1l. The rotor l1 is spring pressei inthe direction oit the fixed element of t e c the mica sheet 18. Therotor 11 compresses that portion of the contacting surfaces of the fixed`and adjustable, elements which are adapted to be operative for anygiven capacity adjustment. In order to maintain the rotor 11 in thisspring pressed relationship to the condenser elements, I have provided aspring member 25 having spring arms 26 which are upwardly intensioned,as indicated in Fig. 4. The spring member 25 is mounted over 'adownwardly projecting annular .flange 27 of the shaft 4. A washer 28 isfitted over the flange, and the flange 27 is then riveted to hold thespring member 25 firmly between the washer and the shoulder 8 of theshaft 4. This construction holds the spring member 25 firmly in placeand permits the upper ends of the spring arms 2G to contact against therotor 11 to urge it upwardly. The arms 26 are of such a length that thepressure is exerted on the rotor 11 at a point between the center of the.rotor and its circumference, thereby insuring that the maximum degreeof pressure shall be exerted on the annular fixed and flexible condenserelements. If pressure were exerted at the cen* ter or periphery of therotor, its effect would not be so readily transmitted as is the casewhere it is exerted directly adjacent to the main surface area of thecondenser elements.

A turning knob 31 is attached to the shaft 4 by means of a screw 32fitting into the screw-threaded aperture 5 of the shaft, whereby theshaft maybe rotated. A pointer 33 is keyed to the turning knob 31, and ashim washer 34 is mounted on the upper face of the upwardly projectingportion 3 of the casing 1. The shim washer 34 is depressed, as indicatedat 35, into a depression formed in the portion 3 of the casing. Therebythe shim washer 34 is prevented from rotation, yet the knob and pointer33 can easily turn. A shim washer 37 is provided on the interior face ofthe casing 1. The shim washer 3 is depressed, as indicated at 38, into adepression 39 formed in the upper interior wall of thecasing 1. Thesetwo shim washers have been found to add greatly to the sturdiness of theconstruction and the strength of the .general shaft assembly, preventingundue play after long use.

Fitting over the lower surface of the casing is -an insulating coverplate 40, held to the casing 1 by means of drive screws 41. An aperture42 is provided in the. cover plate opposite the shaft 4, and apertures43 are formed opposite the eyelets 1G and 23. The cover plate 40 formswith the rotor 11 a recess within which the flexible member 19 may behoused when it-has passed through the slot 12 of the rotor 11.

In operation, by turning the knob 31 in a clockwise direction, the rotor11 is caused to move to pick up a portion of the flexible element 19 tovary the capacity of the condenser.

By reason of the bevelling of the edges 13, the picking up of theflexible element 19 is greatly facilitated, because the friction betweenthe flexible velement and the rotor is reduced to a minimum by reason ofthe sharp entering angle presented to the surfaces. To increase thefacility with which the rotor picks up the flexible element 19, the slot12 is set at an angle to the radii of the rotor 11. This tends to makethe outer edge of the rotor 11 have a slightly greater initialengagement with the flexible element 19, and this edge thereforeoperates as a starting wedge, thus further facilitating the picking upof the flexible element 19. Moreover, one edge 20 of the flexibleelement 19 is upturned, which aids the rotor 11 in picking up theelements, and by reason of the fact that the flexible element is given aconvolute infcnsion in its manufacture and retains this convoluteintension in the assembled device, the flexible element 19 has atendency to spring out through the slot 12 in the rotor.

By rot-ating the rotor, the flexible plate 19 is subjected to a pickingup and laying down operation on the fixed element whereby the capacityof the condenser is Varied. The casing 1 is provided with a scale whichco-opera'tes with the pointer 33 to indicate the adjustment effected.

The utility of the apertured shaft 4 will be apparent from an inspectionof Fig. 6, in which the condenser is shown mounted on the interior of abox 51. An extension shaft 52 is screw-threaded, through the aperture 42in the cover plate 40, into the screw-threaded aperture 5 in the sha ft4. The extension shaft 52 is provided with a conical seat 53 whichengages the conical seat 7 formed in the shaft 4. A knob 54 is screwedby means of a screw 55 into the 'shaft 52, and a suitable scale may beprovided for co-operation with the knob to indicate the adjustment ofthe condenser. Binding posts 56 are provided with extension screws 57which pass through the eyelets 16 and 23 and through the apertures 43 inthe cover plate 40. It is thus apparent that the utility of thecondenser is largely increased by the construction which permits it tobe used in the reverse position if desired.

lVhile I have shown and described the preferred embodiment of nl vinvention` I wish it to be understood that I do not confine myself tothe. precise details of construction herein set forth, by way ofillustration, as it is apparent that many changes and variations may bemade therein, by those skilled in the art, without departing from thespirit of the invention, or exceeding the scope of the appended claims.

I claim: I

1. A variable condenser comprising. a fixed element, an adjustableelement. a shaft, a rotor flotatably mounted on and adapted to turn withthe shaft, a shoulder on the shaft, a washer on the shaft, a pluralityof retaining springs for exerting pressure on the rotor mounted betweenthe Washer and the shoulder, and means for holding the retaining springbetween the Washer and the shoulder.

2. A variable condenser Comprising, a easing, relatively adjustablecondenser elements within the casing, a shaft having a screwthreadedaperture therein at either end, a Cover plate for the easing having anaperture communicating with the shaft, and ine-ans adapted to engageWith the serew-threads of the lapertureswhereby the condenser may beadjusted fot` compression from either side.

3; A variable condenser comprising, a casing, a lixed element, anadjustable element, a rotor having a slot therein through which theadjustable element is adapted to slide, a shaft upon which the rotor ismounted, means attached to the shaft for resiliently pressing the rotoragainst the ixed element, a knob to rotate the shaft, a pointer movingwith the knob,

a shim Washer on the easing held against rotation by an indented portionlitting into a depression in the easing, and another shim Washer on theinterior of the easing and held against .rotation by an indented portionlitting into a depression in the easing.

d. A variable condenser' comprising, a oasing, a fixed element, anadjustable element, a rotor having a slot therein through which theadjustable element is adapted to slide, a shaft upon which the rotor ismount-ed, means attached to the shaft for resiliently pressing the rotoragainst the fixed element, means eX- terior of the casing to rotate theshaft, a shim washer on the casing held against rotation by an indentedportion fitting into a depression in the casing, and another shim Washeron the interior of the easing and held against rotation by an indentedportion fitting into a depression in the casing.

In testimony whereof I affix my signature.

HARRY R. VAN DEVENTER.

